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Sunday, July 5, 2015
- Turtles, frogs, toads and many kinds of birds are imported into Mexico as pets by the thousands every year, but they constitute an environmental and economic threat when they are invasive exotic species.
Since April a reform of the General Law on Wildlife has prohibited imports of such species, but in practice Mexico continues to allow these animals to enter the country. Pet shops rely on them for their lucrative trade.
“The only way to combat invasive species is to effectively ban their sale, because eradication would cost millions of dollars,” María Elena Sánchez, head of the environmental non-governmental organisation (NGO) Teyeliz, told IPS. “This kind of import ban works very well. And it is necessary for national security and food security.”
Invasive species are animals, plants or other organisms introduced by human beings into alien habitats, where they establish themselves and spread causing damage. Typically they have great powers of adaptation and reproduction.
Since the mid-1990s, when markets were opened to foreign trade, Mexico has become a big importer of birds, amphibians and reptiles. Between 2005 and 2010, import permits were granted to bring in some 960,000 wild birds. In 2009 alone, over 239,000 birds were imported from abroad.
“It’s an alarming phenomenon. Mexico has become an importer of exotic wildlife species. The growth of imports has been absolutely exponential. Prices are accessible, and wider distribution has enlarged the market,” Juan Carlos Cantú, head of Mexico programmes for Defenders of Wildlife, a Washington-based NGO, told IPS.
One of the environmental organisations’ concerns is the monk parakeet (Myiopsitta monachus), a native of southern South America, which is regarded as highly invasive and an agricultural pest. Between 2005 and 2010, some 126,260 of these parakeets were imported.
These wild parrots make communal nests in the angles of house roofs or on electricity cables in streets. After reproducing in great numbers, they wreak havoc on maize and sorghum plantations or fruit tree orchards. Environmentalists have documented their presence in the wild in the southern Mexican state of Oaxaca.
In Mexico, approximately 10 million reptiles and amphibians, most of them turtles, are purchased abroad every year for the pet market. There is a risk they may carry diseases harmful to human health, or to that of local wildlife, according to ecologists.
Experts have noted a fungus in pet frogs and toads which causes chytridiomycosis, an infection of the skin in amphibians that is transmitted through water.
This fungus has spread from the United States to Costa Rica; and to the southern Mexican states of Chiapas, Tabasco, Campeche and Oaxaca.
Quite frequently, pet owners tire of them and release them in streets, parks, fields or watercourses, where the animals settle, reproduce and may become dominant.
Article 8h of the Convention on Biological Diversity – an international legally- binding treaty which came into force in 1993 and has been ratified by Mexico – says that states party shall “prevent the introduction of, control or eradicate those alien species which threaten ecosystems, habitats or species.”
In a few weeks’ time, the government will publish the ‘National Strategy on Invasive Species in Mexico: Prevention, control and eradication.’ It held public consultations on a draft version of this document in the first quarter of this year.
During the consultation process it became clear that there was a lack of knowledge about the impact of invasive species, a lack of institutional coordination, no systems for monitoring and early detection, gaps and inconsistencies in the regulations, and shortcomings in import controls and in the control of the expansion of these species.
“One of the most common problems is exotic species that reach a body of fresh water, like the suckermouth catfish (Hypostomus plecostomus), varieties of tilapia (Oreochromis), bigmouth bass (Micropterus salmoides) and even brown trout (Salmo trutta fario),” said Sánchez.
“Once permission is given, the authorities do not monitor the effects that these alien species have,” Cantú emphasised.
Mexico is well aware of what can happen when invasive species enter it and proliferate. In 2006, the nopal moth (Cactoblastis cactorum), an insect native to South America, was found on the islands of Mujeres and Contoy, more than 1,000 kilometres southeast of the Mexican capital. The larva of the nopal moth feeds on the nopal plant, destroying it in the process.
Mexico has 38 native species of nopal or prickly pear, a cactus plant that has become a major national symbol. The nopal is a food source with a thousand- and-one uses, and a staple of the Mexican diet. As such, it is widely cultivated on some three million hectares, and provides a livelihood to thousands of farmers.
The government took action against this threat with a campaign to eradicate the pest, and declared the moth eliminated from the area in 2009.
Another example is that of the gilthead sea bream (Sparus aurata), a native of the Mediterranean Sea and a highly prized dish, which was accidentally released in 2008 into the waters of the Gulf of California, northwest of the Mexican capital. Some of these exotic fish escaped from cages at an Israeli fish farm, and have since proliferated.
It is feared that, as a predatory alien species, it may decimate populations of local fish that only reproduce in this particular gulf. Monitoring of sea bream catches in the area is under way.
Among the goals for 2020 proposed by the government in the strategy document that was circulated for consultation, are the enforcement of laws regulating the introduction and management of invasive species, and identification and surveillance of entry points and diffusion routes for species posing the highest risks.
The executive branch also wishes to create standardised mechanisms and protocols to reduce the risk of entry, establishment and dissemination of invasive species, and to replace them with native species, or those entailing lower risks.